Pretty cool that he's writing his own code to do this (presumably). It reminded me of a neat tutorial for creating grass in Blender:

http://www.youtube.com/watch?v=eshOzshjt90

I created 100% procedural grass using Blender for a book cover recently, and while it didn't have nearly the attention to detail you see in places like Pixar films, the effect was just right for the author's work. I would add that (at least semi-real) shadows are really important for improving the quality of any grass texture.

Thank you! (I'm the author of the post.) I am indeed writing my own code; I'm just using simple functions from Processing.

Thank you very much for the video link. It occurred to me while working on this that video game artists and animators probably do a ton of this, and have much more sophisticated models. Indeed, the result from that video is really, really good. I'm coming from a painting and abstract background. This was my first real exercise in studying natural patterns and textures through algorithmic artwork. I mostly intend to apply it to abstract artwork, but the more realistic approach shown in the video is a different, interesting angle on the same subject.

Does the author release the code behind his generated images?

Hi, I'm the author of the post. I don't normally release my code, but in this case I did post a gist of the main function to Twitter: https://gist.github.com/thobbs/e879b7dad8f3733d58d1

I'm using Quil, which is a Clojure wrapper for Processing. The source is quite dense, so it's hard to understand without following the post. It's mostly about tweaking probability distributions along gradients.